The invention provides a process for producing protein microparticles that can be used for micro-encapsulation, matrix or scaffold formation or formed into films or coatings.
A number of processes are known for making microspheres or microparticles from proteins for a variety of applications, such as food coatings, drug delivery and delayed release of pesticides, fertilizers and agents for environmental cleanup. However, non acidic organic solvents such as ethanol or acetone are often used to dissolve the protein. These solvents are often incompatible with and difficult to remove from food, and there has therefore been a reluctance by the food and pharmaceutical industries to use protein film or microparticle systems. Moreover, the use of non acidic organic solvents poses safety issues with the emission of vapours, the fire hazard that they pose, and the possible residuals that they may leave in the food or pharmaceuticals. Many processes also require the use of elevated temperatures.
U.S. Pat. No. 5,736,178 teaches that film forming colloidal dispersions can be made from dilute aqueous acid solutions of gluten-derived protein by causing the protein to precipitate as microparticles. However, the protein has first to be dissolved in an alcohol such as ethanol, which leads to the disadvantages listed above.
The applicant has therefore identified a need for a process for producing protein microparticles in the absence of non acidic organic solvents such as ethanol.